DIY aquarium monitor system using Arduino (temperature and pH)

Most parts were purchased on eBay. The cost is very cheap, total is about 3000 yen (about 30USD).
Regarding the nice cube clear case, I bought it at Japanese 100 yen shop. Always I can find very cheap and useful parts for DIY there.

Parts List (price):

PH Electrode Probe BNC for Arduino: (JPY 690)
Liquid PH0-14 Value Detect Sensor Module: (JPY 809)
3 Pcs PH Buffer Solution Powder PH Test Meter Measure Calibration 4.00 6.86 9.18: (JPY 97)
1.8 Inch Mini Serial SPI TFT LCD Module Display with PCB Adapter ST7735B IC: (JPY 436)
USB Nano V3.0 ATmega328 16M 5V Micro-controller CH340G board For Arduino: (JPY 284)
Waterproof Digital Thermal Probe or Sensor DS18B20 Length: 1M: (JPY 139)
5/10Pcs Double-sided PCB Circuit Board Universal Prototype Strip Breadboard 7BC(JPY 384)
Cube clear case: (JPY 100)